PCI: Fix /sys warning when sriov enabled and card is hot removed

sysfs is a bit stricter now and emits warnings in more cases.

For SRIOV hotplug, we are calling pci_stop_dev() for each VF first
(after we update pci_stop_bus_devices) which remove each VF subdir.  So
double check the VF dir in /sys before trying to remove the physfn link.
Signed-of-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/iov.c

@@ -173,7 +173,13 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset)
 
 	sprintf(buf, "virtfn%u", id);
 	sysfs_remove_link(&dev->dev.kobj, buf);
-	sysfs_remove_link(&virtfn->dev.kobj, "physfn");
+	/*
+	 * pci_stop_dev() could have been called for this virtfn already,
+	 * so the directory for the virtfn may have been removed before.
+	 * Double check to avoid spurious sysfs warnings.
+	 */
+	if (virtfn->dev.kobj.sd)
+		sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 
 	mutex_lock(&iov->dev->sriov->lock);
 	pci_remove_bus_device(virtfn);